A6 Murder DNA evidence

[JamesDean]

That is the issue, the expectation was to find the DNA of the rapist and victim from the semen and vaginal fluids

No you are leaping ahead again and still assuming that any male DNA found is from semen. That may have been the expectation but once the process of extracting and amplifying of DNA is underway there is no way of knowing what type of genetic material was the source of the base DNA.

..... therefore what has happened to the DNA from the rapists' semen?

That is an entirely separate issue unrelated to whether or not contamination has to be semen.

[Victor]

I have no problem with expecting (or hoping) to find DNA profiles. The point I was making originally is that it is a false assumption that any DNA profiles must have originated from semen. To do so eliminates the possibility of contamination from any other type of genetic material. I don't accept that as reasonable.

That is the issue, the expectation was to find the DNA of the rapist and victim from the semen and vaginal fluids, therefore what has happened to the DNA from the rapists' semen?

Without the raw data it is impossible to say whether any semen was microscopically visually identified, and it may be for this reason that they concluded that the contaminant had to be semen.

[Victor]

Tut tut! You are attributing that quote to me and it is simply a reversal of what Caz said.

I appreciate that it is a reversal of Caz, but it was included in your post and is the only place where I could copy and quote it from.

[JamesDean]

No it isn't. It is vital. Every schoolchild is taught in science that you first work out what you expect to find, and then to compare what you expect to get with what you actually get, and in most cases give a %age yield.

In this case you expect to find DNA profiles from VS, the rapist, possibly MG and maybe some of the investigators\technicians and other contaminants (including JH).

I have no problem with expecting (or hoping) to find DNA profiles. The point I was making originally is that it is a false assumption that any DNA profiles must have originated from semen. To do so eliminates the possibility of contamination from any other type of genetic material. I don't accept that as reasonable.

[JamesDean]

At least this doesn't include me!

I started out believing JH was innocent and the DNA evidence persuaded me otherwise, which is where a lot of other people such as Graham started too.

Tut tut! You are attributing that quote to me and it is simply a reversal of what Caz said.

[Victor]

Hi James, Victor, All,

I’d be interested in hearing your thoughts regarding the DNA evidence used to convict Ronald Castree of the 1975 murder of Lesley Molseed. There appear to be one or two parallels with the DNA evidence in the A6 case.

In the Real Crime documentary shown on ITV last night it was claimed that just one bit of forensic evidence from 1975 had survived, in the form of an envelope containing a small piece of tape used on an item of Lesley’s clothing to pick up any fibres etc that may have been left by her killer. Because semen had been found on her knickers, it was thought there might just be a chance that some had been lifted up onto the surviving tape, which could provide the killer's DNA profile. According to the documentary it was the first time a DNA profile had been obtained in this way. The case was 25 years old in 2000, and was described as the oldest ever worked on at the time (?). They also had only one shot at it because the tape would be destroyed in the process.

In the event they struck lucky and discovered sperm heads in the extracted material and obtained the vital DNA profile. But no match was found in the data base and their work was kept secret so as not to alert the killer. The final breakthrough came in 2005, when Ronald Castree was accused of rape by a prostitute. A routine DNA swab gave them the match they had been waiting for and he is now serving life.

Is there any suggestion that sperm heads were looked for or found on the A6 knicker fragment? If none were found, should they have been? Or would the additional 15 years in this case have provided a reasonable explanation?

And crucially, does anyone have any doubts about the process leading to Castree being positively identified as Lesley Molseed's killer from that little piece of tape? No potential flaws in the DNA technique? The findings perfectly valid?

Love,

Caz
X

Hi Caz,

I saw the documentary last night too and was amazed at the number of similarities to the Hanratty case with regard to the DNA evidence, but there seem to be very few people jumping and shouting that Castree is innocent and the DNA was wrong.

The major point I took from the film was how appalling the treatment of Stefan was, and that the evidence that cleared him was available in 1975 and he should never have been charged.

KR,
Vic.

[Victor]

I agree with you that certain observations made on this thread about the appeal judgement give the definite impression of coming from a position of believing that Hanratty was guilty, and therefore believing that the DNA evidence was not only conclusive or reliable, and should have been admissible - it must actually have been correct.

At least this doesn't include me!

I started out believing JH was innocent and the DNA evidence persuaded me otherwise, which is where a lot of other people such as Graham started too.

[Victor]

It's irrelevant what you expect to find on any exhibit. Having expectations significantly increases the likelihood of misinterpretation. It's a well known phenomena that people tend to see what they expect to see.

No it isn't. It is vital. Every schoolchild is taught in science that you first work out what you expect to find, and then to compare what you expect to get with what you actually get, and in most cases give a %age yield.

In this case you expect to find DNA profiles from VS, the rapist, possibly MG and maybe some of the investigators\technicians and other contaminants (including JH).

What was found was VS, MG and JH. And from there you draw the conclusions.

If Dr Evison was convinced then I'm sure the judgment would have said that.

Fair enough, I should have used the words "mostly persuaded" instead of convinced, hence "he seemed to accept" with the unwritten "with some reservations" because his reservations were detailed previously.

[JamesDean]

Absolutely not. I'm working forwards from the available sample and working out what I would expect to find. You don't even have to know the results of the test to do this bit. To prove this answer this one simple question:-

What DNA do you expect to find on that knicker fragment?

It's irrelevant what you expect to find on any exhibit. Having expectations significantly increases the likelihood of misinterpretation. It's a well known phenomena that people tend to see what they expect to see.

Can you explain then why you are interpretting the judgement as "Dr Evison was bullied" rather than "Dr Evison was convinced by the reasoned argument of the prosecution"?

If Dr Evison was convinced then I'm sure the judgment would have said that.

[Victor]

You are making the same mistake of logic that was made at the appeal. You are taking the result of the DNA test and then working backward to make it fit your expectations. Forget magically disappearing DNA. The issue of why only three profiles were detected is a question that has to be answered further down the line. To state that only semen could be the source of contamination is absurd and is a convenient assumption to limit the possible mechanism by which contamination could have occurred. If you cannot accept that contamination does not have to be semen then there is no point in continuing this discussion.

Absolutely not. I'm working forwards from the available sample and working out what I would expect to find. You don't even have to know the results of the test to do this bit. To prove this answer this one simple question:-

What DNA do you expect to find on that knicker fragment?

After that you can compare what you expect to find with what was actually found.

Dr Evison being bullied into seeming to agree that the contaminant had to be semen has nothing to do with me pre-supposing that JH is innocent. I don't pre-suppose anything; I am simply taking a fresh look at the rationale that was used to determine that the DNA was conclusive. To that end I am not convinced but that does not mean that I have a closed mind. I could accuse you of exactly the same thing as you appear to be locked into the belief that the judgment is beyond criticism.

Can you explain then why you are interpretting the judgement as "Dr Evison was bullied" rather than "Dr Evison was convinced by the reasoned argument of the prosecution"?

[JamesDean]

Is there any suggestion that sperm heads were looked for or found on the A6 knicker fragment? If none were found, should they have been? Or would the additional 15 years in this case have provided a reasonable explanation?

Hi Caz

If there were no sperm heads present on the fragment then there would be no DNA detected from sperm in the semen stains. It would not be possible, however, to identify individual sperm heads visually as belonging to different men; that can only be achieved by analysing the various DNA present on the fragment, some of which may not have come specifically from sperm.

I don't have any comments to make on other cases as I'm not familiar with them. However, that does not imply that I have any issue with the value of DNA analysis per se. Each case has to be taken on its own merits and I'm only looking at the A6 case.

Regards
James

[JamesDean]

Hi Victor,

I agree with you that certain observations made on this thread about the appeal judgement give the definite impression of coming from a position of believing that Hanratty was innocent, and therefore believing that the DNA evidence was not only inconclusive or unreliable, and should not have been admissible - it must actually have been wrong.

Sorry Caz but I don't follow that argument at all. It's just as true to say:

I agree with you that certain observations made on this thread about the appeal judgement give the definite impression of coming from a position of believing that Hanratty was guilty, and therefore believing that the DNA evidence was not only conclusive or reliable, and should have been admissible - it must actually have been correct.

[JamesDean]

Why is it a flaw in logic? The sample was a semen stained knicker fragment, and logically you'd expect the DNA profiles discovered to be those people who'd had sex, ie, VS and MG and the rapist. Three profiles were found therefore you have the problem of working out where the rapists semen got to if you suppose that JH wasn't the rapist and his DNA was introduced as a contaminant.

You are making the same mistake of logic that was made at the appeal. You are taking the result of the DNA test and then working backward to make it fit your expectations. Forget magically disappearing DNA. The issue of why only three profiles were detected is a question that has to be answered further down the line. To state that only semen could be the source of contamination is absurd and is a convenient assumption to limit the possible mechanism by which contamination could have occurred. If you cannot accept that contamination does not have to be semen then there is no point in continuing this discussion.

To use words like "bullied" you are pre-supposing that JH is innocent and have closed your mind to the possibility that he was the rapist.

Dr Evison being bullied into seeming to agree that the contaminant had to be semen has nothing to do with me pre-supposing that JH is innocent. I don't pre-suppose anything; I am simply taking a fresh look at the rationale that was used to determine that the DNA was conclusive. To that end I am not convinced but that does not mean that I have a closed mind. I could accuse you of exactly the same thing as you appear to be locked into the belief that the judgment is beyond criticism.

[caz]

Hi Victor,

I agree with you that certain observations made on this thread about the appeal judgement give the definite impression of coming from a position of believing that Hanratty was innocent, and therefore believing that the DNA evidence was not only inconclusive or unreliable, and should not have been admissible - it must actually have been wrong. This is a step too far, because it relies on the original case evidence for support and there is nothing there, nor anything about the DNA findings themselves, to indicate that the latter did in fact identify the wrong man or fail to identify the right one.

The very best that can be argued dispassionately and without bias or gut feelings creeping in is that the original case evidence was not strong enough to make the conviction 100% safe, and the DNA testing would not have been reliable enough on its own to render it safe. If that was all that was being said around here, I'd have some sympathy for the view and call it stalemate unless anything new turned up. But it's not just a case of claiming Hanratty should not have been found guilty without more damning evidence. People seem to be using this supposed lack of ultimate proof to make him innocent - which it very clearly doesn't.

Love,

Caz
X

[caz]

Hi James, Victor, All,

I’d be interested in hearing your thoughts regarding the DNA evidence used to convict Ronald Castree of the 1975 murder of Lesley Molseed. There appear to be one or two parallels with the DNA evidence in the A6 case.

In the Real Crime documentary shown on ITV last night it was claimed that just one bit of forensic evidence from 1975 had survived, in the form of an envelope containing a small piece of tape used on an item of Lesley’s clothing to pick up any fibres etc that may have been left by her killer. Because semen had been found on her knickers, it was thought there might just be a chance that some had been lifted up onto the surviving tape, which could provide the killer's DNA profile. According to the documentary it was the first time a DNA profile had been obtained in this way. The case was 25 years old in 2000, and was described as the oldest ever worked on at the time (?). They also had only one shot at it because the tape would be destroyed in the process.

In the event they struck lucky and discovered sperm heads in the extracted material and obtained the vital DNA profile. But no match was found in the data base and their work was kept secret so as not to alert the killer. The final breakthrough came in 2005, when Ronald Castree was accused of rape by a prostitute. A routine DNA swab gave them the match they had been waiting for and he is now serving life.

Is there any suggestion that sperm heads were looked for or found on the A6 knicker fragment? If none were found, should they have been? Or would the additional 15 years in this case have provided a reasonable explanation?

And crucially, does anyone have any doubts about the process leading to Castree being positively identified as Lesley Molseed's killer from that little piece of tape? No potential flaws in the DNA technique? The findings perfectly valid?

Love,

Caz
X